N2O as reactant rather than pollutant at wastewater treatment plants: Life Cycle Assessment and Techno-Economic Analysis of N2O-to-phenol

N2O emissions-reducing technologies are essential to reduce wastewater treatment plant (WWTP) greenhouse gas (GHG) emissions. In this study, we perform a life cycle assessment (LCA) and techno-economic analysis (TEA) of a technology that intentionally produces N2O from WWTP N and uses this gas as an oxidant in the production of phenol and co-product N2. We compare the cost and sustainability of producing phenol and N2 with this technology and via conventional routes (cumene-to-phenol, cryogenic distillation, and pressure swing absorption to N2). Depending on the co-product allocation method, the median cumulative energy demand of the phenol produced from WWTP nitrogen is 30% to 50% higher than phenol from the cumene process, while the global warming potential of phenol produced via this pathway ranges from 10% lower to 40% higher than conventional routes to this chemical. However, depending on WWTP size, level of N2O recovery, and the market price of feedstocks and products, producing phenol at WWTP with this technology can produce a positive internal rate of return. We conclude that this technology could be applicable for large-scale WWTPs, but technological advancements are needed.